1. Field of the Invention
This invention pertains generally to semiconductor processes, and more particularly to formation of polycrystalline semiconductor materials at low temperatures.
2. Description of Related Art
In the manufacture of very large scale integrated circuits, polycrystalline-silicon (poly-Si) films are typically formed directly by low-pressure chemical vapor deposition (LPCVD) at temperatures above 600° C., using silane as the precursor gas. Use of such a high process temperature renders this approach unsuitable for formation of poly-Si films on low-cost glass and plastic substrates and on substrates with completed CMOS integrated circuits. Various other techniques have been attempted, with less than ideal results, toward crystallizing amorphous silicon films without subjecting the material to excessive temperatures for the given application.
Accordingly, a need exists for a method of readily forming polycrystalline semiconductor without subjecting the substrate to high temperatures, or requiring the use of complex processing steps. These needs and others are met within the present invention, which overcomes the deficiencies of previously developed poly formation methods.